Genome reveals pigs' history, and promise for medical research

Scientists have assembled the genome of a Duroc sow, learning a great deal… (L. Brian Stauffer )

There’s a lot a researcher can learn, it turns out, from studying some cells from a common farm pig.

Assembling the genome, or DNA letters, of a domestic Duroc pig named T.J. Tabasco and comparing it with the genomes of the wild boar, the mouse, the dog, the horse, the cow — and yes, the human — members of the Swine Genome Sequencing Consortium were able to determine that Asian and European pig lineages split 800,000 to 1.6 million years ago, suggesting that the two branches of the pig family were domesticated separately in West and East Asia.

They also learned that pigs have a very large number of functional olfactory genes but a relatively dull sense of taste. (The Duroc’s DNA had fewer taste receptor genes for bitter flavors, for example.)

Discoveries such as these aren’t mere trivia. Having a high-quality reference genome for the domestic pig — a DNA catalog scientists can compare with future samples — could help those who study pigs as a model for human disease. T.J.’s DNA, it turned out, shared a number of protein aberrations that have been implicated in human disorders such as obesity, dyslexia, Parkinson’s disease and Alzheimer’s disease.

The last common ancestor shared by pigs and people lived between 79 million and 97 million years ago, the researchers said.

The new data, along with DNA information collected from wild boars, could also help farmers breed better pigs by pointing the way toward wild variants that could be advantageous to domesticated animals, said scientists involved in the work.

“We can easily go find genes that might be still in the wild that we could use for breeding purposes today,” study leader Lawrence Schook, vice president for research at the University of Illinois in Champaign, said in a statement.

In addition to University of Illinois scientists, researchers from Wageningen University in the Netherlands and the University of Edinburgh in Scotland headed the consortium.

Also on Wednesday, a team of researchers from China and Denmark released genome data collected from an inbred mini-pig, the Wuzhishan pig, that is often used in medical research. That work, which was published in the journal GigaScience, focused on genes and proteins in pigs that are counterparts to targets for drugs in humans.

While many of the genes and proteins were similar between the two species, others were very different. This provided a better sense of what types of drug testing are feasible on the mini-pig and what types aren’t, the researchers said.

For further explanation of why sequencing the pig genome matters — and a fetching photo of the late T.J. Tabasco’s mounted head — read “Pig Geneticists Go the Whole Hog,” also in Nature.